Mobo with PCI-e 16 and Card says PCI-e 2.0

[Lohengramm]

Hello folks, so heres the story. My mobo has a PCI-E 16x (running at 16x) and i'm planning on buying a HD5770 1GB GDDR5 XFX, The card says it needs a pci-e 2.0 port.

So the question is, can I use the card on my motherboard? And if I do, how does it affect it? What are the differences between PCI-E 16x and PCI-E 2.0 16x?

It will bottleneck, and how?

My specs are:
Phenom II x4 920 @ 2.8Ghz (Stock)
HD4670 1gb ddr2
Mobo Gigabyte M68M-S2P
4Gb RAM (800Mhz)
1TB HD Western Digital
PSU 550w.

Thanks in advance and forgive me for my ignorance, googled already and found no answers.

 

[jaguarskx]

If you are going to buy a PCI-e 2.1 card then you need to install it in a motherboard with a PCI-e 2.0 slot. There are some compatibility issues between a PCI-e 2.1 card and a PCI-e 1.0 slot.

I have a HD 5850 (PCI-e 2.0) running just fine in my Abit mobo which has a PCI-e 1.0 slot.

 

[Lohengramm]

HD5770 is needs a PCI-e 2.0, not 2.1. Mine is 1.0.

Still need a concrete answer.